This invention relates to improvements in internal grinders.
In one type of internal grinder known in the art, the grinding wheel dressing device is secured to the bed and the grinding wheel head is moved both in the axial direction of the spindle and in a direction which is at right angles to the longitudinal axis of the spindle. In another type of internal grinder known in the art, the grinding head dressing device is secured to the bed, and the grinding wheel head is moved in the axial direction of the spindle, while the head stock is moved in a direction which is at right angles to the longitudinal axis of the spindle. In the former type of grinder, it is possible to mount a direct sizing device on the grinding wheel head side. However, the grinding wheel head must be moved to the position of the grinding wheel dressing device each time dressing is carried out, thereby making the dressing operation troublesome. In the latter type of grinder, a dressing operation can be performed with less difficulty than in the former type of grinder. However, it is necessary to mount a direct sizing device on the head stock side, and thus the direct sizing device must be withdrawn from its operative position each time the worked workpiece is replaced by a new workpiece. Moreover the latter type of grinder has a disadvantage in operation in that a cut operation necessary for effecting grinding of a workpiece must be performed by the operator with his left hand.